#include<stdio.h>
#include<unistd.h>
#include<string.h>
int main()
{
/*//c语言
 printf("hello printf\n");
 fprintf(stdout,"hello fprintf!!\n");
//系统
 const char *str="hello write!!\n"; 
 write(1,str,strlen(str));
 fork();*/ 
  printf("hello printf!\n");
  perror("perror!");
  fprintf(stdout,"stdout:hello fprintf\n");

  fprintf(stderr,"stderr:hello fprintf\n");
  return 0;
}
